[DOCS-417] Add doc for option to disable index prefetching Created: 17/Aug/12  Updated: 13/Nov/23  Resolved: 28/Aug/12

Status: Closed
Project: Documentation
Component/s: Server
Affects Version/s: None
Fix Version/s: mongodb-2.2, Server_Docs_20231030, Server_Docs_20231106, Server_Docs_20231105, Server_Docs_20231113

Type: Task Priority: Major - P3
Reporter: Andrew Leung (Inactive) Assignee: Sam Kleinman (Inactive)
Resolution: Done Votes: 0
Labels: None
Remaining Estimate: Not Specified
Time Spent: Not Specified
Original Estimate: Not Specified

Issue Links:
Related
related to SERVER-6718 option to disable index prefetching a... Closed
Participants:
Days since reply: 11 years, 25 weeks, 1 day ago

 Description   

Config option for indexPrefetch commandline flag:

Command line flag --replIndexPrefetch
Parameter replIndexPrefetch
values: none, _id_only, all
"all" is the default if unspecified.


New parameter replIndexPrefetch.
Settable via the command line or use setParameter() command on a running server.
Only valid on a server started with --replSet parameter.
This allows a user to disable the prefetching of all index pages prior to the application
of a replicated op on a secondary.
For most use cases, prefetching all indexes for a given op will provide good performance.
For use cases that do many in-place updates to documents in a collection with many indexes
that are unaffected by such updates, using the '_id_only' setting may provide better performance
than the 'all' setting. The '_id_only' setting only prefetches index pages for the _id index,
which will always be used to find the document needed to be updated.
The 'none' setting will be used for debugging only; there should be no production use cases for
this setting.
getParameter() supports getting the current value of this parameter.



 Comments   
Comment by auto [ 28/Aug/12 ]

Author:

{u'date': u'2012-08-28T09:05:52-07:00', u'email': u'samk@10gen.com', u'name': u'Sam Kleinman'}

Message: DOCS-417 corrections
Branch: master
https://github.com/mongodb/docs/commit/1dc73cb407530b9fc5ad1355b11fe0188b2a21cf

Comment by auto [ 28/Aug/12 ]

Author:

{u'date': u'2012-08-28T08:34:34-07:00', u'email': u'samk@10gen.com', u'name': u'Sam Kleinman'}

Message: DOCS-417: added documentation of --replIndexPrefetch
Branch: master
https://github.com/mongodb/docs/commit/7bec88850a54170ab4b1c4e5c3b39129f1c2abdc

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